Fig. 8.

Overexpression of KDM8 confers upregulation of neuroendocrine markers and renders prostate cancer cells more sensitive to killing by EZH2 inhibitors. a Immunobloting assay of KDM8 expression in C4-2B cell line and its enzalutamide-resistant derivative, C4-2B-MDVR. α-tubulin and GAPDH were used as a loading control. b Correlation analysis between gene expression levels of KDM8 and EZH2 in prostate cancer patients (right panel) and normal controls (left panel) from TCGA dataset extracted from Oncomine database. Pearson’s correlation (r) values are shown in each graph. c Cell survival curves of C4-2B and C4-2B-MDVR cells treated with EZH2 inhibitors. Cells were exposed to the EZH2 inhibitors GSK343 and GSK126 in different doses from 0 to 50 μg/ml for 72 h followed by MTT assay. Data were expressed as the mean ± S.D. of triplicate experiments. The values of IC₅₀ were calculated and shown. The regression lines represent the fit to a non-linear regression model using GraphPad Prism. d qRT-PCR analysis of KDM8, EZH2, AR, and neuroendocrine markers mRNA expression. Parental cell lines (C4-2B) and the enzalutamide-resistant derivative (C4-2B-MDVR) were transfected with si-RNAs targeting KDM8 (si-KDM8) or non-targeting control (si-NT) for 48 h. The relative mRNA levels of the above genes were normalized to 18S rRNA. Data were represented as the mean ± S.D. of triplicate experiments. Values in C4-2B cells transfected with si-NT were set to 1. *^,#p < 0.05, **^{, ##}p < 0.01, by paired Students’ t-test. e Model of KDM8-driven CRPC and neuroendocrine markers expression via AR–EZH2 axis